A fuel cell is known as a power generation system having a high energy efficiency, which generates electric power through electrochemical reaction of mainly hydrogen and oxygen, or hydrogen-rich gas obtained by reforming natural gas or the like and air, which are introduced to a fuel electrode and an oxygen electrode, respectively. Therefore, there has been proposed a portable type power generating system utilizing the fuel cell have been proposed.
Japanese Patent Kokai Publication No. 5-190196 proposes a portable power source wherein hydrogen-oxygen fuel cell is operated by using hydrogen absorbed in a hydrogen storage alloy in a pressure canister. This portable power source has such problems as the hydrogen storage alloy container is too expensive to be widely used, and the container is too heavy to be used in a portable power source.
Japanese Patent Kokai Publication No. 6-310166 also proposes a portable fuel cell power source comprising a fuel pressure canister filled with aqueous solution of methanol at a high pressure instead of hydrogen, a fuel reforming device which modifies the aqueous solution of methanol discharged from the fuel pressure canister into a gas consisting mainly of hydrogen, a fuel cell which generates electricity by using the hydrogen-rich gas as the fuel, and a cabinet that houses these components. This power source has such a problem that the fuel pressure container which contains the aqueous solution of methanol at a high pressure must have a high withstand pressure while such a pressure container is not suited to a portable apparatus and is not commercially available, resulting in an inconvenience for wide commercial applications.
For these reasons, portable power generation systems commercialized at present are still based on a gasoline engine, although it is a problem that small gasoline engine power generation systems of output power within several hundreds of watts have energy efficiency as low as 10% or less.